Law of Conservation of Mass

Front

What is the Law of Conservation of Mass?

Back

Mass is never created or destroyed in a chemical reaction.

Front

What is a subscript in a chemical formula?

Back

A subscript is a number written below and to the right of an element symbol that indicates the number of atoms of that element in a molecule.

Front

In the reaction A + B --> C, if A has 5g and C has 9g, how many grams does B have?

Back

4g

Front

How many sulfur atoms are in the reactants of the equation: 2SO2 + 2H2O2 --> 2H2SO4?

Back

2

Front

What happens to the mass of reactants in a chemical reaction?

Back

The total mass of the reactants equals the total mass of the products.

Front

What is a coefficient in a chemical equation?

Back

A coefficient is a number placed in front of a chemical formula to indicate how many molecules or moles of that substance are involved.

Front

When CaCO3 is heated, what happens to its mass?

Back

The sum of the products’ masses equals the mass of the CaCO3.

Front

What does it mean when we say mass is conserved?

Back

It means that the total mass remains constant in a closed system during a chemical reaction.

Front

What is the difference between a physical change and a chemical change?

Back

A physical change alters the form of a substance but not its chemical composition, while a chemical change results in the formation of new substances.

Front

What is the role of reactants in a chemical reaction?

Back

Reactants are the starting substances that undergo a chemical change to form products.